U.S. patent number 7,952,024 [Application Number 12/155,994] was granted by the patent office on 2011-05-31 for u-turn bus bar.
This patent grant is currently assigned to Denso Corporation. Invention is credited to Fumio Kondo, Daisuke Okushita.
United States Patent |
7,952,024 |
Okushita , et al. |
May 31, 2011 |
U-turn bus bar
Abstract
A U-turn bus bar comprises a body portion constituting a linear
essential part formed of a conductive plate member, having an
overall thickness (t) and an overall width (2b); at least a
terminal portion expanded in the direction perpendicular to the
longitudinal direction of the body portion; and a connection hole
formed at one end of the body portion. The body portion includes a
U-turn bend formed by bending the body portion into a U-turn
shape.
Inventors: |
Okushita; Daisuke (Kariya,
JP), Kondo; Fumio (Nagoya, JP) |
Assignee: |
Denso Corporation (Kariya,
JP)
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Family
ID: |
40131257 |
Appl.
No.: |
12/155,994 |
Filed: |
June 12, 2008 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20080308292 A1 |
Dec 18, 2008 |
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Foreign Application Priority Data
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Jun 18, 2007 [JP] |
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2007-159969 |
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Current U.S.
Class: |
174/68.2;
439/212 |
Current CPC
Class: |
H02G
5/02 (20130101) |
Current International
Class: |
H02G
5/00 (20060101) |
Field of
Search: |
;439/883,507,510,212,949
;174/68.2,72B |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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A-64-10509 |
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Jan 1989 |
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JP |
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U-1-135610 |
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Sep 1989 |
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JP |
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A-11-299056 |
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Oct 1999 |
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JP |
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A-2000-209739 |
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Jul 2000 |
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JP |
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A-2001-314019 |
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Nov 2001 |
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JP |
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A-2002-281645 |
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Sep 2002 |
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JP |
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A-2004-23844 |
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Jan 2004 |
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JP |
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A-2004-32960 |
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Jan 2004 |
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JP |
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Other References
Office Action issued in Japanese Patent Application No. 2007-159969
on Aug. 24, 2009 with English Translation. cited by other.
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Primary Examiner: Zarroli; Michael C
Attorney, Agent or Firm: Oliff & Berridge, PLC
Claims
The invention claimed is:
1. A U-turn bus bar comprising: a body portion constituting a
linear essential part formed of a conductive plate member, having
an overall thickness (t) and an overall width (2b); at least a
terminal portion expanded in the direction perpendicular to the
longitudinal direction of the body portion; and a connection hole
formed at one end of the body portion; wherein the body portion
includes the U-turn bend formed by bending, in the U-turn shape, a
single wire member of a conductive material having the width (b) of
one half of the overall width (2b) and the same thickness (t) as
the overall thickness, wherein the wire member is divided into a
first wire member on one side and a second wire member on the other
side at the U-turn bend, wherein the body portion also includes a
parallel portion having the first wire member and the second wire
member coupled to each other, the parallel portion being fixed by a
spot, wherein the second wire member of the body portion of the bus
bar is formed with at least a protrusion for a terminal, being bent
and projected in such a manner so as to be spaced from the first
wire member, and wherein the U-turn bend has a connection hole
formed by coupling the first wire member and the second wire member
in annular shape.
2. The U-turn bus bar according to claim 1, wherein the wire member
is formed of a single square member of a conductive material having
the width (b) one half of the overall width and the same thickness
(t) as the overall thickness, and wherein the flat surface of the
first square member and the flat surface of the second square
member are coupled to each other in parallel.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a bus bar used in a circuit inside an
electrical connection box, etc., of an automotive vehicle.
2. Description of the Related Art
In recent years, a bus bar has been used as a power terminal of an
inverter in a hybrid car. For example, bus bar 11 shown in FIG. 3,
has an essential part with a thickness t and width 2b as shown in
FIG. 2B, which determines an allowable current therein. Bus bar 11
is manufactured in a predetermined shape by punching a plate into a
blank with thickness t and width 2b and bending it.
Bus bar 11 includes body portion 13 which is the essential linear
part, as a current conductor. Body portion 13 has wide terminal
portion 15 expanded in the horizontal direction perpendicular to
the longitudinal direction, in order to be connected to an electric
wire, etc. One end of body portion 13 has multiple bends and formed
with connection hole 17, which is connected to a terminal of a
conductor by bolts, etc. Bus bar 11 is also used for connecting
other types of conductors (for example, cable, wiring harness) to
terminal portion 15 or connecting hole 17.
Bus bar 11 is required to have high conductivity and heat radiation
efficiency which is sufficient to supply a large current.
Especially, in order to improve heat radiation efficiency, the
surface area per unit length is required to be increased and
because of this, this requirement is conventionally carried out by
increasing thickness t and width 2b.
Therefore, there is a problem that the volume per unit length is
increased, which means that a plate to be punched may become bulky,
and at the same time increasing the geometrical moment of inertia,
resulting in difficulty in bending and manufacturing.
This type of bus bar is disclosed in Japanese Unexamined Patent
Publication No. 2002-281645.
SUMMARY OF THE INVENTION
The object of this invention is to solve the problem described
above and provide a bus bar capable of ensuring sufficient
conductivity, heat radiation efficiency, and easiness in
manufacturing.
In order to solve the aforementioned problem, according to one
aspect of this invention, a U-turn bus bar comprising a parallel
portion (24) formed by bending a single wire member (23, width b
and thickness t) in U-turn shape is provided.
According to one aspect of the invention, the surface area for heat
radiation can be increased and the geometrical moment of inertia
can be reduced, compared with a bus bar of a single wire member
(width 2b and thickness t) having an equivalent sectional area for
current passage. Therefore, radiation efficiency and manufacturing
can be remarkably improved.
When the wire member (23) has a rectangular section, the surface
area can be increased by the two opposed surfaces of the parallel
wire members and the heat radiation efficiency can be improved,
compared with the case of using a single rectangular wire member
having an equivalent sectional area for current passage. The
geometrical moment of inertia can also be reduced, so that
manufacturing can be remarkably improved.
According to another aspect of the invention, a U-turn bus bar is
provided, having at least a joint (26, 28) formed to couple the
wire members in the parallel portion (24). A U-turn bus bar is
provided, wherein a gap (30) is formed between the wire members in
the parallel portion (24) other than the joint (26, 28).
Thus, the parallel wire members can be easily fixed. At the same
time, radiation efficiency can be improved, since heat escapes from
the gap.
According to still another aspect of the invention, a U-turn bus
bar is provided, wherein the wire members are spaced apart from
each other in order to form a hole (39) for connecting an
electrical conductor at the U-turn bend (25). A U-turn bus bar is
provided, wherein at least a part of the gap is formed so that a
protrusion (31, 33) for a terminal of a conductor can be formed.
Therefore, by simply bending the wire member, a connection hole and
a connector for welding the terminal can be formed. As a result,
manufacturing can be improved. No material is wasted, compared with
the aforementioned case manufactured by punching, so that material
cost can be greatly reduced.
According to yet another aspect of the invention, a U-turn bus bar
is provided comprising:
a body portion (29) constituting a linear essential part formed of
a conductive plate member, having an overall thickness (t) and an
overall width (2b);
at least a terminal portion (31, 33) expanded in the direction
perpendicular to the longitudinal direction of the body portion;
and
a connection hole (39) formed at one end of the body portion;
wherein the body portion (29) includes the U-turn bend (25) formed
by bending in the U-turn shape, a single wire member (23) of a
conductive material having the width (b) of one half of the overall
width and the same thickness (t) as the overall thickness,
wherein the wire member (23) is divided into a first wire member
(23a) on one side and a second wire member (23b) on the other side
regarding the U-turn bend (25), wherein the body portion (29) also
includes a parallel portion (24) having the first wire member (23a)
and the second wire member (23b) coupled to each other, at least a
part of the parallel portion (24) being fixed by a spot,
wherein the second wire member (23b) of the body portion (29) of
the bus bar is formed with at least a protrusion (31, 33) for a
terminal, being bent and projected in such a manner so as to be
spaced from the first wire member (23a), and
wherein the U-turn bend (25) has a connection hole (39) formed by
coupling the first wire member (23a) and the second wire member
(23b) in annular shape.
As a result, as compared with the use of a single wire member
having an equivalent sectional area for current passage, the
surface area for heat radiation can be increased and geometrical
moment of inertia can be reduced. Therefore, according to another
aspect of this invention, the radiation efficiency and
manufacturing process can be improved remarkably.
In order to solve the above mentioned problem, according to a
further aspect of the invention, a U-turn bus bar is provided,
wherein the wire member (23) is formed of a single square member of
a conductive material having the width (b) one half of the overall
width and the same thickness (t) as the overall thickness, and
wherein the parallel portion (24) of the body portion (29) has the
flat surface of the first square member (23a), and the flat surface
of the second square member (23b), being coupled to each other in
parallel.
As a result, the surface area can be increased by an amount equal
to the opposed surfaces of the parallel wire members, compared to
using a single rectangular wire member having an equivalent
sectional area for current passage. Therefore, radiation efficiency
can be remarkably improved. The geometrical moment of inertia can
be reduced so that manufacturing can also be remarkably
improved.
The reference numerals inserted in the parentheses following the
names of the respective means described above represent an example
of correspondence with the specific means described in the
embodiments below.
The present invention may be more fully understood from the
description of preferred embodiments of the invention, as set forth
below, together with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A, 1B, and 1C are respectively a plan view, a front view and
a side view showing a U-turn bus bar according to an embodiment of
the invention.
FIG. 2A shows a sectional view of the bus bar shown in FIG. 1 and
FIG. 2B shows a sectional view of a conventional bus bar.
FIGS. 3A, 3B, and 3C are respectively a plan view, a front view and
a side view showing a conventional bus bar.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
An embodiment of the invention will be explained below with
reference to FIGS. 1 and 2.
In FIG. 1, numeral 21 designates a U-turn bus bar according to an
embodiment of the invention. U-turn bus bar 21 is configured by
bending a linear square member 23 of a conductive material with
width b and thickness t in U-shape. Bus bar 21 has first square
member 23a on one side and second square member 23b on the other
side.
First and second square members 23a, 23b are coupled to each other
at U-turn bend 25 and formed in a parallel state as parallel
portion 24. End portions 27 opposing to U-turn bend 25 are welded
at spot-welding portion 26 by spot-welding. Another spot-welding
portion 28 is formed by spot-welding at parallel portion 24. There
is gap 30 between first square member 23a and second square member
23b except the spot-welding portions 26, 28. In this way, as shown
in FIG. 2A, bus bar 21 has thickness t and width 2b as a whole.
This bus bar 21 has substantially linear bus bar body 29 with
spot-welding portion 28. Second square member 23b of the bus bar
body 29 is formed with first protrusion 31 and second protrusion
33, which are bent and projected so as to be spaced away from the
first square member 23a. First protrusion 31 and second protrusion
33 are adapted to be coupled with terminals of electrical
conductors from other parts by welding, etc.
Furthermore, this bus bar body 29 is formed with a rising portion
35 vertically rising from an end of first and second square members
23a, 23b. The upper end portion of the rising portion 35 has a
horizontal portion 37, which is bent in stepped form and extended
horizontally from the upper end of rising portion 35. U-turn bend
25 of the horizontal portion 37 is formed with a connection hole 39
by arranging the first square member 23a and the second square
member 23b in spaced relationship to each other. This connection
hole 39 is for connecting other devices electrically and
mechanically by inserting a bolt or the like therein.
As described above, U-turn bus bar 21 is configured in U-turn shape
by bending the conductive square member with width b and thickness
t. As shown in FIG. 2A, U-turn bus bar 21 has totally thickness t
and width 2b as a conductor.
As compared with bus bar 11 shown in FIG. 2B, although bus bar 21
of this embodiment has the same sectional area for current passage
as bus bar 11, the radiation area is increased by twice due to
surface 23x of first square member 23a and the surface 23y of
second square member 23b, as shown in FIG. 2A. Therefore, the
radiation efficiency can be improved remarkably. Since bus bar 21
has less geometrical moment of inertia than conventional bus bar
11, it is easy to bend a blank in the manufacturing process.
Furthermore, since the first protrusion 31, the second protrusion
33, the U-turn bend 25 and the connection hole 39 are formed simply
by bending a single continuous square member 23, these parts can be
easily formed, thereby remarkably shortening the manufacturing
process.
As compared with the manufacturing process in which these parts are
punched in the shape shown in FIG. 3A, the manufacturing process of
bus bar 21 does not waste blanks and the blank cost can be greatly
reduced, since bus bar 21 is made from a single wire member.
Although the embodiment described above uses a square member having
a rectangular section as a wire member, the invention is not
limited to such a material but may use a member having a cross
section circular, hexagonal or in other shapes.
According to the embodiment described above, the U-turn bend 25 is
connected to other terminals with a bolt, a screw or the like.
However, the invention is not limited to this configuration, and
the U-turn bend 25 may be connected to other wire members or
terminals by welding or brazing.
Furthermore, according to the embodiment described above, the
parallel portion is coupled by spot welding. The invention is not
limited to this coupling method. The first square member 23a and
the second square member 23b may be coupled to each other using
other coupling means such as caulking, brazing or bonding.
While the invention has been described by reference to specific
embodiments chosen for purposes of illustration, it should be
apparent that numerous modifications could be made thereto by those
skilled in the art without departing from the basic concept and
scope of the invention.
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